As explained on the Massachusetts government website, the new Massachusetts Child Safety Passenger Law, as of July 10, 2008, will
require children to ride as passengers motor vehicles in a federally approved child passenger restraint that is properly fastened and secured until they are 8 years old OR over 57" tall. The expanded law will require a booster seat/safety belt combination for children who have outgrown a child safety seat - typically when they are above age five or 40 pounds - until they are 8 years old OR over 57" tall. The Massachusetts Safety Belt Law requires safety belt use by those 13 years of age and older.
The federal regulations for child safety seats can be found at 49 CFR 571.213. For comprehensive information on passenger safety for children of all sizes, see the following from the website of the American Academy of Pediatrics: Car Safety Seats: A Guide for Families 2008.
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